This invention pertains to the field of collecting, sorting and analyzing particles in an aerosol and, more particularly, to a method and apparatus for collecting an aerosol, sorting particles within the aerosol and subjecting the particles to redundant analysis for the purpose of identifying the particles.
The separation and capture of particles or aerosols from air or other fluid streams are of concern in two contexts: first, in determining the type and concentration of such particles/aerosols and, second, in cleansing the fluid stream for subsequent use. For example, the detection or extraction of airborne biological or chemical warfare agents, biological contamination in confined spaces, such as aircraft or hospitals, or industrial pollutants (either in ambient air or in smokestacks) may be required in various scenarios.
Much effort has been expended in the past in the collection of aerosols, the extraction of particles from aerosols and the analysis and identification of particles in aerosols.
The prior art includes methods and apparatus for analyzing particles in gases in possible target areas, including public buildings, critical infrastructure such as water supply facilities, and defensive installations such as military bases. The prior art includes sampling of the atmosphere from possible target areas. In some prior art technologies, all of the particles from a sample are isolated, and then the particles are analyzed. In other prior art methods, the volume of the sample is reduced, and a representative portion of the particles is analyzed.
The prior art recognizes that the avoidance of false positives is of critical importance. A false positive with respect to explosive particles, pathogen particles, radioactive particles, and any other adverse particles, may lead to unnecessary evacuations and possible injury and death. In addition, if a particular method and apparatus result in repeated false positives, then the level of confidence in that method and apparatus may be degraded to the point that vigorous responses to protect the public will become difficult to achieve. However, to date, none of the prior art adequately addresses the problem of false positives.